I just switched to Google Messages for my texting app. So far, it does not have this problem. I am able to use it to reply to the group texts that Samsung Messages can't. I would suggest that anyone with this problem give another texting app a try until Samsung gets this fixed.
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I currently have three conversation that won't let me reply. Each one only has 2-3 people on it. Looking at all my texts and conversations I can't see any consistency regarding the carrier or phones they are using (Android, iPhone) so I don't think that is it. Also, I noticed that for Most of my messages and group conversations, each message in it says MMS next to it. When I open the a text or group conversation a very annoying message almost always pops-up at the bottom for a moment that says "converting to multimedia message...". For some reason, this doesn't happen on a few text messages, however. When I open one of the conversation that don't work, I don't get that pop-up. I wonder if for these conversations aren't working because the app is not converting it to an MMS? Is there a way to force the conversation to convert it to MMS?
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Also, when I scroll through all the conversations, the ones that have this problem have a little white N with a blue background just under the date in the bottom right corner right where the pin would be if I were to pin the conversation. Yes, this happens in safe mode.
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Same thing for me. I'm on Cricket. My prevous phone was a Note 5. I can reply to some Group messages but not all Group messages. Doesn't matter if I'm on cellular or wifi. Also, the icon that is to the right of the text box is the Samsung Voice Recorder icon. It's white with light blue background on mine but looks like this and is on every text message so I doubt it has anything to do with it. https://play.google.com/store/apps/details?id=com.sec.android.app.voicenote&hl=en_US I don't seem to have this problem with Google Messages. I was able to send using it. Model number Android 8.1.0, Samsung experience number 9.5 software build number M1ajq.n960u1ues1arj9 Samsung Messages 5.0.25.53
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